1. Field of the Invention
The present invention relates to a heating power adjusting apparatus of a hot blast heater, and more particularly to a heating power adjusting apparatus of a hot blast heater which variably adjusts heating power of a burner via pressure fluctuation through selective switching between the cross-sectional areas of orifices in a flow space of air supplied to a burner head.
2. Description of the Related Art
In general, a hot blast heater is developed so as to be used to raise the indoor temperature of an open space, and executes a function of supplying heated air to a specific space to raise the inner temperature of the space.
Such a hot blast heater is used to indirectly raise the inner temperature of a specific space which is one of industrial facilities, such as a factory, or various places, such as a barn and a vinyl house, through heating of air. Conventional hot blast heaters may be divided into an electric heating type and a combustion heating type according to air heating methods.
First, an electric heating type hot blast heater heats sucked air using heat generated from heat wires or a heater according to power supply, and then supplies the heated air to a specific space so as to achieve heating effects. Such an electric heating type hot blast heater is mainly applied if a space desired to be heated is narrow.
Further, a combustion heating type hot blast heater heats sucked air using heat generated by combustion of fuel in a burner, and then supplies the heated air to a specific space so as to achieve heating effects. Such a combustion heating type hot blast heater is actively applied if a space desired to be heated is relatively broad or if power is not effectively supplied.
Particularly, since it is expected that the combustion heating type hot blast heater has relatively high heat efficiency, as compared with the electric heating type hot blast heater, the combustion heating type hot blast heater is widely used now. That is, the combustion heating type hot blast heater is mainly used in a factory, a vinyl house, a barn, etc., having a relatively wide area.
However, the conventional combustion heating type hot blast heater causes air pollution due to exhaust gas generated during combustion, and thus a safe exhaust path must be guaranteed and a purification function must be provided.
Further, such a hot blast heater must have a function of adjusting a temperature to raise an indoor temperature to a desired level. Therefore, temperature adjustment of the conventional combustion heating type hot blast heater is carried out by variably adjusting an amount of fuel supplied to a combustion chamber of the burner according to a pressure level of air generated by operation of a vane pump.
In this case, the pressure of air generated from the vane pump is obtained by controlling a rotating speed, such control of the rotating speed of the vane pump employs an electronic control method in which a waveform of input voltage of a motor is adjusted and thus requires high costs to manufacture the combustion heating type hot blast heater, and employs a complicated electronic speed control method and thus causes a heavy financial burden to normally maintain, repair and manage equipment.